Wireless telegraph calling device



Apr. 24, 1923. 1,452,925

w. H. NOTTAGE ET AL WIRELESS TELEGRAPH CALLING DEVICE Filed Dec. 18,1920 2 Sheets-Sheet 1 Fi .2 P

Apr. 24, 1923.

W. H. NOTTAGE ET AL WIRELESS TELEGRAPH CALLING DEVICE Filed Dec. is,1920 2 Sheets-Sheet 2 .N' I L avg- 041 I'D I W H. NOTZAGE F 8 w 12,P/z/f/UN Patented Apr. 24, 1923.

UNITED STATES WILLIAM HOCKLEY NOTTAGE AND THOMAS DIXON PARKIN, OFCHELMSEORD,

ENGLAND, ASSIGNOBS TO THE RADIO CORPORATION OF AMERICA, 01 NEW YORK, N.Y., A CORPORATION OI DELAWARE.

WIRELESS TELEGRAPH CALLING DEVICE.

Application filed December 18, 1920. Serial No. 431,599.

5 47 Goldlay Road, Chelmsford, England,

British subjects, have invented new and useful Improvements in WirelessTelegraph Calling Devices, of which the following is a s ecificationaccompanied by drawings.

his invention relates I to wireless telegraphic calling devices of thetype in which impulses are transmitted at regular intervals and arereceived by a balance wheel relay, or the like, which has a naturaloscillation period equal to the interval between successive impulses-sothat though the relay may be unaffected by ordinary signals, yet when atrain of impulses at predetermlnedintervals is incident upon thereceiver the oscillations of the relay are increased by the impulsessufiiciently to enable it to actuate a bell or other signal or operatein some way an electric circuit for the control of apparatus.

According to this invention we employ for transmitting and receiving theimpulses timing mechanism comprising a spring controlled balance wheeloscillated by an electromagnet the circuit of which is interrupted bythe oscillations of the wheel.

, The preferred arrangement is illustrated by the accompanying drawings,in which- Figs. 1 and 2 are, respectively, front and side elevations ofour timed transmitter,

Fig. 3 shows a modification of our timed transmitter,

Figs. 4 and 5 are, respectively, end and front elevations of ouroscillation relay, and

Figs. 6 and 7 and 8 are diagrams of the method of connecting ourreceiving apparatus.

Figures 1 and 2 show a front and side elevation (taken from the right ofFig. 1) of an oscillating wheel (hereinafter referred to as a timedtransmitter). A spindle D which can oscillate in fixed bearings E isconnected by a spring H to an adjustable support J and carries thearmature B of an electromagnet A C the poles A of which are arranged onopposite sides of the spindle D. The armature B supports a ring K ofnon-magnetic material in order to give the movement the required momentof inertia. The spindle D carries also a spring blade F on the end of abattery and the which is a contact piece adapted as the spindle in itsoscillation reaches a certain position to impinge upon a stationarycontact G and thus to complete a circuit comprisin windings C of theelectromagnet A C.

The stationary contact G is so arranged that the pressure between F andG is sufficient to make a good electrical contact but not to have on thetime period a controlling effect at all comparable'to the controlexerted by the spring H.

vlVIounted on spindle D is a cam L of insulatmg material arranged topress together two sprmgs M and N each fitted with contact pieces in thecircuit of which is located the apparatus to be controlled.

The cam L is shaped so that the point of the oscillation of the spindleD at which M and N make contact and the time during which M and N are incont-act relative to the per od of oscillation of D are adjustable andsprings M and N are arranged so'that the pressure between them and thecam does not have on the time period of D a controlling effect at allcomparable to the control exerted by H.

Alternately the cam L and spring contacts M and N may be omitted asdescribed below in connection with Fig. 3.

The spindle and the parts carried by it are carefully balanced so thatthe gravity may exert no directive force upon the system no matter whatthe position of the spindle.

In order that the tension of spring H may readily be adjusted thesupport J to one end of which H is secured, is carried by a worm wheel Pwhich can be turned about the axis of the spindle D by a worm Q providedwith a milled head.

The timed transmitter as described is so arranged that shortening thearc of travel before the potential energy due to the tension of thespring H rear-hes value equal to that of the kinetic energy given by animpulse due to a current through 0 of certain strength will shorten thetime between successive contacts. If therefore a smaller current be sentthrough C, the tension of H when the spindle comes to rest will be lessand the arc of travel'will be less and therefore the time period tendsto shorten. On the other hand, the reduction in the current reduces thecontrol exerted by the magnetic impulses and therefore the time periodtends to increase. These two effects therefore tend to counteract oneanother and hence the intervals between transmitted impulses aresubstantially unaffected by wide variations in the current.

To start the .timed transmitter, a tapping key U may be provided and, asshown 1n Figure 3 connected in parallel with F and G so that All may beenergized by a few taps roughly in synchronism w th the time period ofthe movement. start the spindle oscillating and the osc 1l lations willthen be automatically maintained.

Included in the circuit of contacts M and N is an electromagnet R V thearmature R of which carries a contact Alternatively the contacts M and Nmay be omitted from the timed transmitter and the coils of theelectromagnet- R V connected in series with contacts F and G.

The contact S will control the wireless telegraph transmittin circuitso'as to send.

A: and 5.

The movement consist of a spindle d carrying a spring h and a steel ringa with a non-magnetic bar is fixed to it along a diameter for securingthe ring to the spindle.

The ring is magnetized with its poles at opposite ends of a diameter;the spindle d carries a light arm j on one end of which is a contactpiece 7. The period of oscillation of the movement is made equal to thetime interval between the impulses sent by the timed transmitter.

The spindle d works in fixed bearings c e and has coils c 0 arranged soas to surround the ring a which has its poles placed at right angles tothe common axis of c 0.

A contact 9 is fixed to a light flexible arm g carried on a pillar gwhich is arranged so that 9 may be raised or lowered and so that contactf impinges on 9 when the motion of thearm is sufficient.

These contacts 7 g are included in a circuit by which an alarm bell maybe sounded or other device actuated when they close.

-Tl1e oscillating relay as described may be actuated by the signals fromthe distant timed transmitter in several ways.

The preferred method illustrated in Fig. ure 6 is to connect the coils cc in series with the anode of a valve M and the anode battery Nassociated therewith. Any apparatu as a telephone .transformer 0 usedfor the ordinary working of the receiver may also be included withoutdetriment to our device These taps will which in turn need not bedisconnected when it is not in use.

The grid of the valve M is connected to one end of a transformer windingI, the the other end of whi'eh'is connected through a resistance Rofseveralhundred magohms to the filament circuit of the valve. Thearrangement is such that the incidence of an impulse causes a diminutionin the current through the coils and this diminution starts theoscillation of spindle d.

It will be seen that no incident signal however a strong can vary thecurrent through the 'coils to a greater extent than to make it zero and,therefore, the maximum impulse imparted to the movement is limited sothat if the distance between contacts f and g be made sufficient, nochange in the current-through the coils due to ordinary signals can besufficient to cause the contacts to close thecircuit.

As shown in Figure 7, the contacts f g are shunted by an inductance Sand capacity T and are connected in series with a battery, an alarm Vsuch as an electric bell and a hold ing electromagnet W which has a pairof .anode and anode battery circuit of valve M so that whenever thecontacts of the relay are closed by a diminution of the current throughthe coil an impulse due to a current of definite value is sent throughthe coils c 0, no matter what the strength of the signals which actuateS.

Having now particularly described and ascertained the nature of our saidinvention and in what manner the same is to be performed, we declarethat what we claim is 1. In a wireless telegraph timing mechanism, aspring controlled balance wheel oscillated by an electromagnet thecircuit of which is interrupted by the oscillations of the wheel,substantially as-described.

2. In wireless telegraph timing mechanism, the combination of a balancewheel on a spindle, rotatable in fixed bearings, a pluwith a pluralityfor said balance wheel, means for normally maintaining said balancewheel in a predetermined position, and electro magnetic means forcausing said wheel to oscillate.v

4. The combination claimed in claim 3 of contacts cont-rolled by saidbalance wheel.

5. T he combination claimed in claim 4 in which one of said contactscontrols said electro-magnetic means.

6. The combination claimed in claim 5 with an electromagnetic relaycontrolled by anotherv of said contacts.

1 Dated the 19th day of November, 1920.

\VILLIAM HOCKLEY NOTTAGE. THOMAS DIXON PARKIN.

